Angelina baked 100 cookies she ate half of the cookies and gave 3/10 of the cookies how many cookies were left over
Angelina ate 1/2 * 100 = <<1/2*100=50>>50 cookies.
She gave 3/10 * 100 = <<3/10*100=30>>30 cookies.
So, the total number of cookies left over is 100 - 50 - 30 = <<100-50-30=20>>20 cookies. Answer: \boxed{20}.
To find out how many cookies were left over, we need to subtract the cookies Angelina ate and the cookies she gave away from the total number of cookies.
Angelina ate half of the cookies, which means she ate 1/2 * 100 = 50 cookies.
She also gave away 3/10 of the cookies, so she gave away 3/10 * 100 = 30 cookies.
Now let's calculate the number of cookies left over:
Total cookies - Cookies Angelina ate - Cookies Angelina gave away = Cookies left over
= 100 - 50 - 30
= 20
Therefore, there were 20 cookies left over.